Multilayer ceramic capacitor and method of manufacturing the same

Abstract

The invention provides a multilayer ceramic capacitor and a method of manufacturing the same. The multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an external electrode disposed on an outer side of the capacitor body, in which the multilayer ceramic capacitor includes Ti and Ge, and in which a content of Ge based on 100 moles of Ti is about 0.01 moles to about 20 moles.

Description

Technical Field

[0001] The present disclosure relates to a multilayer ceramic capacitor and a method of manufacturing the multilayer ceramic capacitor. Background Art

[0002] Recently, with the rapid development of multifunctionality and miniaturization of electronic devices, the miniaturization and performance improvement of electronic components have also developed rapidly. In addition, the demand for high reliability of electrical devices used in automobiles, network equipment, etc. and electronic components used in industry has also increased significantly.

[0003] To meet such market demands, competition for technological development of passive components such as inductors, capacitors, and resistors has accelerated. In particular, great efforts have been required to capture the market by developing various multilayer ceramic capacitor (MLCC) products, whose applications and uses as passive components have continued to increase.

[0004] In addition, multilayer ceramic capacitors are manufactured by stacking dielectric layers and internal electrodes, and are used in various electronic devices such as mobile phones, notebook computers, and liquid crystal televisions (LCD TVs).

[0005] Recent technological advancements have led to demands for smaller and higher-capacitance multilayer ceramic capacitors, which in turn necessitates reducing the thickness (thinning) of internal electrodes and dielectric layers. As dielectric layer thickness decreases, the electric field strength applied per layer becomes relatively stronger, reducing capacitor reliability and also leading to a decrease in electrostatic capacitance due to degraded electrode connectivity. Summary of the Invention

[0006] An aspect of an embodiment provides a multilayer ceramic capacitor having improved capacitance, reliability, and temperature characteristics.

[0007] However, the problems that the embodiments attempt to solve are not limited to the aforementioned problems, and can be expanded in various ways within the scope of the technical ideas included in the embodiments.

[0008] According to an embodiment, a multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode disposed on an outer surface of the capacitor body, wherein the multilayer ceramic capacitor includes Ti and Ge, and in the multilayer ceramic capacitor, a content of Ge based on 100 mols of Ti is about 0.01 mol to about 20 mols.

[0009] The dielectric layer includes Ti and Ge, and the inner electrode includes Ni and Ge. When the average molar content of Ge in the inner electrode relative to 100 moles of Ni in the inner electrode is X, and the average molar content of Ge in the dielectric layer relative to 100 moles of Ti in the dielectric layer is Y, the relationship between X and Y can satisfy Equation 1.

[0010] [Equation 1] X / Y ≥ 1 X can be from about 0.1 mole to about 15 moles.

[0011] Y can be from about 0.05 mole to about 10 moles.

[0012] The dielectric layer may include a plurality of dielectric grains and grain boundaries located between at least two of the plurality of dielectric grains. The plurality of dielectric grains may include a main component and a secondary component, and the main component may include Ba m TiO3 (0.995 ≤ m ≤ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or a combination thereof.

[0013] The secondary component may include Ge, Zr, Dy, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ga, In, Ba, La, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu, Hf, or a combination thereof.

[0014] The average thickness of the inner electrode can be from about 0.05 μm to about 2 μm.

[0015] The average thickness of the dielectric layer can be from about 0.05 μm to about 10 μm.

[0016] A multi-layer ceramic capacitor according to another embodiment includes: a capacitor body including a dielectric layer and internal electrodes; and external electrodes provided on an outer surface of the capacitor body, wherein the multi-layer ceramic capacitor includes Ti and Ge, and in the multi-layer ceramic capacitor, the content of Ge based on 100 moles of Ti is from about 0.01 mole to about 20 moles, the dielectric layer includes a plurality of dielectric grains and grain boundaries located between at least two of the plurality of dielectric grains, and the grain boundaries include Ge, Ge oxide, or a combination thereof.

[0017] The plurality of dielectric grains may include a main component and a sub-component, and the main component may include Ba m TiO3(0.995 ≤ m ≤ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3(0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3(0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3(0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), or a combination thereof.

[0018] The sub-component may include Ge, Zr, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ba, Hf, Ga, In, La, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or a combination thereof.

[0019] The plurality of dielectric grains may further include Ge, Ge oxide, or a combination thereof.

[0020] The internal electrodes may include a conductive metal and Ge.

[0021] The internal electrodes may include an alloy containing a conductive metal and Ge.

[0022] The external electrodes may include a sintered metal layer in contact with the capacitor body, and the sintered metal layer may include a conductive metal and Ge.

[0023] The average thickness of the internal electrodes may be from about 0.05 μm to about 2 μm.

[0024] The dielectric layer may have an average thickness of about 0.05 μm to about 10 μm.

[0025] According to yet another embodiment, a multilayer ceramic capacitor includes: a capacitor body including a dielectric layer and an inner electrode; and an outer electrode disposed on an outer surface of the capacitor body, wherein the dielectric layer includes Ti and Ge, and the inner electrode includes Ni and Ge, and when an average molar content of Ge in the inner electrode relative to 100 moles of Ni in the inner electrode is X, and an average molar content of Ge in the dielectric layer relative to 100 moles of Ti in the dielectric layer is Y, a relationship between X and Y satisfies Formula 1: [Formula 1] X / Y≥1.

[0026] The dielectric layer may include Ge in the form of Ge oxide, and the internal electrode may include Ge in the form of an alloy.

[0027] In the multilayer ceramic capacitor, the content of Ge may be about 0.01 mol to about 20 mol based on 100 mol of Ti.

[0028] The external electrode may include Ge.

[0029] A method of manufacturing a multilayer ceramic capacitor according to another embodiment includes: applying a conductive paste on a dielectric green sheet to form an internal electrode pattern on the dielectric green sheet, stacking a plurality of the dielectric green sheets having the internal electrode pattern formed thereon to form a dielectric green sheet stack, and -14 MPa to about 1.0×10 -10 The dielectric green sheet stack is sintered at an oxygen partial pressure of 100 MPa to form a capacitor body.

[0030] The method may further comprise: -9 MPa to about 1.0×10 -5 The capacitor body is annealed at an oxygen partial pressure of 100 MPa.

[0031] The conductive paste may include Ge oxide and / or an alloy containing Ge.

[0032] The multilayer ceramic capacitor may include Ti, and in the multilayer ceramic capacitor, a content of Ge may be about 0.01 mol to about 20 mol based on 100 mol of Ti.

[0033] The multilayer ceramic capacitor according to the embodiment has advantages of improved capacitance, reliability, and temperature characteristics.

[0034] However, various and beneficial advantages and effects of the present disclosure are not limited to the foregoing description and can be more easily understood in the course of explaining specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a perspective view showing a multilayer ceramic capacitor according to an embodiment.

[0036] Figure 2 It is along Figure 1 A cross-sectional view of a multilayer ceramic capacitor taken along line II' in FIG.

[0037] Figure 3 It shows Figure 1 An exploded perspective view of the stacked structure of the capacitor body. DETAILED DESCRIPTION

[0038] Hereinafter, example embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the example embodiments of the present disclosure. The drawings and descriptions are to be considered illustrative and non-restrictive in nature. Throughout the specification, the same reference numerals represent the same elements. In addition, the accompanying drawings are provided to help easily understand the embodiments disclosed in this specification, and the technical spirit disclosed in this specification is not limited by the accompanying drawings, and it will be understood that the present disclosure includes all variations, equivalents, and alternatives contained in the spirit and technical scope of the present disclosure.

[0039] Terms including ordinal numbers (such as first and second) are used to describe various components, but the components are not limited by the terms. The terms are only used to distinguish one component from another.

[0040] When a component is referred to as being “connected” or “coupled” to another component, it is understood that the component may be directly connected or coupled to the other component, or other components may be present between the one component and the other component. Conversely, when a component is referred to as being “directly connected” or “directly coupled” to another component, it is understood that no other components are present between the one component and the other component.

[0041] In this specification, it will be understood that the terms "include" and "have" are intended to specify the presence of the features, numbers, steps, operations, constituent elements and components or their combinations described in the specification, and do not exclude the possibility of the pre-existence or addition of one or more other features, numbers, steps, operations, constituent elements and components or their combinations. Therefore, unless explicitly described to the contrary, the word "include" and variations such as "comprises" or "have" will be understood to imply the inclusion of the stated elements but not the exclusion of any other elements.

[0042] As used herein, the terms “about” and “approximately” may provide industry-accepted tolerances for their corresponding terms and / or relativity between items, such as ±1%, ±5%, or ±10% of the actual value, as well as other suitable tolerances.

[0043] Hereinafter, various embodiments and exemplary modifications are described in detail with reference to the accompanying drawings.

[0044] Figure 1 is a perspective view showing a multilayer ceramic capacitor 100 according to an embodiment, Figure 2 It is along Figure 1 The cross-sectional view of the multilayer ceramic capacitor 100 is taken along line II′, and Figure 3 It shows Figure 1 An exploded perspective view of the stacked structure of the capacitor body.

[0045] To clearly describe this embodiment, directions are defined as follows: The L-axis, W-axis, and T-axis directions shown in the drawings represent the length, width, and thickness directions of the capacitor body 110, respectively. The thickness direction (T-axis direction) may be perpendicular to the wide surface (main surface) of the sheet-like component (i.e., capacitor body 110) and may be used, for example, as the same concept as the stacking direction of the dielectric layers 111. The length direction (L-axis direction) may be parallel to the wide surface (main surface) of the sheet-like component and perpendicular to the thickness direction (T-axis direction), and may be, for example, the direction in which the first and second external electrodes 131 and 132 face each other. The width direction (W-axis direction) may be parallel to the wide surface (main surface) of the sheet-like component and perpendicular to the thickness direction (T-axis direction) and the length direction (L-axis direction). The length of the sheet-like component in the length direction (L-axis direction) may be longer than the length of the sheet-like component in the width direction (W-axis direction).

[0046] Reference Figures 1 to 3 The multilayer ceramic capacitor 100 according to the embodiment may include a capacitor body 110 and first and second external electrodes 131 and 132 provided on both ends of the capacitor body 110 opposite to each other in a length direction (L-axis direction).

[0047] The multilayer ceramic capacitor 100 according to the embodiment includes a capacitor body 110 and external electrodes 131 and 132 arranged on the outside of the capacitor body 110. The capacitor body 110 includes a dielectric layer 111 and internal electrodes 121 and 122. The multilayer ceramic capacitor 100 includes Ti and Ge, and in the multilayer ceramic capacitor 100, the content of Ge is about 0.01 mol to about 20 mol based on 100 mol of Ti.

[0048] The present disclosure has the advantage of improving the capacitance, reliability, and temperature characteristics of the multilayer ceramic capacitor by optimizing the content of Ge in the multilayer ceramic capacitor 100 .

[0049] If the Ge content per 100 mol of Ti in the multilayer ceramic capacitor 100 is less than about 0.01 mol, the temperature characteristics of the capacitor cannot be sufficiently improved, and if the Ge content per 100 mol of Ti in the multilayer ceramic capacitor 100 exceeds about 20 mol, it may be difficult to sufficiently improve the reliability of the capacitor.

[0050] In the multilayer ceramic capacitor 100 according to the embodiment, the dielectric layer 111 includes: a plurality of dielectric grains; and a grain boundary between at least two dielectric grains, wherein the grain boundary includes Ge, Ge oxide, or a combination thereof.

[0051] For example, the dielectric grains may include a main component and a subsidiary component, and the dielectric grains may further include Ge, Ge oxide, or a combination thereof. Hereinafter, the main component and the subsidiary component included in the dielectric grains will be described.

[0052] For example, the internal electrodes 121 and 122 may include a conductive metal and Ge, and as a specific example, the internal electrodes 121 and 122 may include an alloy of the conductive metal and Ge.

[0053] For example, the external electrode may include a sintered metal layer contacting the capacitor body 110 , and the sintered metal layer may include a conductive metal and Ge.

[0054] Ge (germanium) is an element having a stronger tendency to oxidize than Ni, which is a main material of the internal electrodes 121 and 122 .

[0055] When such Ge is added to a conductive paste for forming internal electrodes during the manufacture of a multilayer ceramic capacitor and fired together with Ni in a reducing atmosphere, some of the Ge may be uniformly present in the form of a Ni—Ge alloy within the internal electrodes 121 and 122 .

[0056] The Ni-Ge alloy can reduce the grain boundary energy and surface tension of Ni, thereby improving the smoothness and connectivity of the internal electrodes 121 and 122. If the smoothness of the internal electrodes 121 and 122 is improved, the intensity of the electric field applied to each dielectric layer can be dispersed even if the thickness of the dielectric layer 111 is reduced.

[0057] In addition, by alloying Ge (a semi-metal) with Ni, the insulation at the interface between the dielectric layer 111 and the internal electrodes 121 and 122 can be improved, thereby improving reliability. In addition, during the alloying process with Ge, the sintering rate of Ni is delayed, which further improves electrode connectivity and enables the realization of a capacitor with higher capacitance.

[0058] In addition, the remaining Ge may diffuse toward the dielectric layer 111 in the form of Ge and / or Ge oxide (GeO 2 ), and at this time, the Ge and / or Ge oxide may diffuse uniformly along the grain boundaries within the dielectric layer 111. In addition, some of the Ge and / or some of the Ge oxide may diffuse into the dielectric grains.

[0059] At this time, because Ge oxide has a lower melting point than BaTiO3 (the main component of the dielectric grains), it can liquefy during the capacitor firing process. The liquefied Ge oxide promotes the grain growth of the dielectric crystals, thereby increasing the dielectric constant of the capacitor.

[0060] In addition, the dielectric grains may have a core-shell structure. In this case, the liquefied Ge oxide may improve the capacitance change rate characteristics of the capacitor with respect to temperature by increasing the shell fraction within the dielectric grains.

[0061] A method of measuring the content of Ge relative to Ti in the multilayer ceramic capacitor 100 is as follows.

[0062] First, a sample of the multilayer ceramic capacitor 100 was prepared. 0.1 g of the sample was weighed and placed in a pressure bottle, and 6 mL of hydrochloric acid and 2 mL of nitric acid were added to the pressure bottle to prepare a mixture. The mixture was then heat-treated at approximately 180°C for approximately 1 hour, and a dissolved sample was prepared by additional ultrasonic treatment. After filtering the dissolved sample through a 0.45 μm filter, the Ti content (weight %) and Ge content (weight %) in the sample were analyzed using an inductively coupled plasma-optical emission spectrometer (ICP-OES). The Ge content in the multilayer ceramic capacitor 100 was then obtained by converting the weight % of each element to mol % and then converting the mol % of Ge based on 100 moles of Ti. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used.

[0063] Capacitor body The capacitor body 110 may have, for example, an approximately hexahedral shape.

[0064] In this embodiment, for ease of explanation, in the capacitor body 110, two surfaces opposite to each other in the thickness direction (T-axis direction) are defined as a first surface and a second surface, and two surfaces coupled to the first surface and the second surface and opposite to each other in the length direction (L-axis direction) are defined as a third surface and a fourth surface, and two surfaces coupled to the first surface and the second surface and coupled to the third surface and the fourth surface and opposite to each other in the width direction (W-axis direction) are defined as a fifth surface and a sixth surface.

[0065] As an example, the first surface (lower surface) may be a surface facing the installation direction. In addition, the first to sixth surfaces may be flat; however, the present embodiment is not limited thereto, and for example, the first to sixth surfaces may be curved surfaces with a convex central portion, and the boundaries (i.e., edges) of each surface may be rounded.

[0066] The shape, size, and number of stacked dielectric layers 111 of the capacitor body 110 are not limited to those shown in the drawings of this embodiment.

[0067] The capacitor body 110 is formed by stacking a plurality of dielectric layers 111 in a thickness direction (T-axis direction) and firing the plurality of dielectric layers 111, and includes a plurality of dielectric layers 111 and first and second internal electrodes 121 and 122 alternately arranged in the thickness direction (T-axis direction), with the dielectric layer 111 interposed between the first and second internal electrodes 121 and 122.

[0068] In this case, adjacent dielectric layers 111 in the capacitor body 110 may be integrated so that the boundaries between the dielectric layers are difficult to see without using a scanning electron microscope (SEM).

[0069] Furthermore, capacitor body 110 may include an active area and footprints 112 and 113 .

[0070] The active region is a portion that contributes to forming capacitance of the multilayer ceramic capacitor 100. As an example, the active region may be a region where the first and second internal electrodes 121 and 122 stacked in the thickness direction (T-axis direction) overlap.

[0071] Covering regions 112 and 113 are edge portions in the thickness direction and may be located on both surfaces of the active region in the thickness direction (T-axis direction). These covering regions 112 and 113 may be stacked on the upper and lower surfaces of the active region, respectively, and each covering region may be composed of a single dielectric layer or two or more dielectric layers.

[0072] The capacitor body 110 may also include side cover regions. These side cover regions are widthwise edge portions and may be located on both widthwise (W-axis) surfaces of the active region. These side cover regions can be formed by stacking dielectric green sheets coated with a conductive paste for forming internal electrodes and firing them. When forming the conductive paste layer on the surfaces of the dielectric green sheets, the conductive paste may be applied only to portions of the dielectric green sheet surfaces and may not be applied to both widthwise sides of the dielectric green sheet surfaces.

[0073] The cover regions 112 and 113 and the side cover regions serve to prevent the first and second internal electrodes 121 and 122 from being damaged by physical stress and / or chemical stress.

[0074] dielectric layer The dielectric layer 111 may include a dielectric, and the dielectric may include a main component and a secondary component.

[0075] The main component is a dielectric matrix with a high dielectric constant and contributes to forming the dielectric constant of the multilayer ceramic capacitor 100.

[0076] The dielectric layer 111 may include: a plurality of dielectric grains; and grain boundaries located between at least two dielectric grains, where the grain boundaries include Ge, Ge oxides, or a combination thereof.

[0077] For example, the dielectric grains may include a main component and a secondary component, and the dielectric grains may further include Ge, Ge oxides, or a combination thereof.

[0078] For example, the main component may be a barium titanate-based compound and may be a dielectric material, and the dielectric material includes, for example, Ba m TiO3 (0.995 ≤ m ≤ 1.010), (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20), Ba m (Ti 1-x Zr x )O3 (0.995 ≤ m ≤ 1.010, 0 < x ≤ 0.10), (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3 (0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20) or a combination thereof.

[0079] As an example, the main component may include BaTiO3, Ba(Ti , Zr)O3, Ba(Ti, Sn)O3, (Ba, Ca)TiO3, (Ba,Ca)(Ti, Zr)O3, (Ba, Ca)(Ti, Sn)O3, (Ba, Sr)TiO3, (Ba, Sr)(Ti, Zr)O3, (Ba, Sr)(Ti,Sn)O3, or a combination thereof.

[0080] For example, the secondary components may include germanium (Ge), zirconium (Zr), dysprosium (Dy), vanadium (V), manganese (Mn), chromium (Cr), silicon (Si), aluminum (Al), magnesium (Mg), tin (Sn), antimony (Sb), gallium (Ga), indium (In), barium (Ba), lanthanum (La), yttrium (Y), actinium (Ac), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), hafnium (Hf), or combinations thereof.

[0081] The dielectric may also include ceramic additives, organic solvents, binders, dispersants, or combinations thereof.

[0082] For example, at least one of the plurality of dielectric grains may have a core-shell structure.

[0083] A dielectric grain having a core-shell structure includes a core and a shell surrounding at least a portion of the core within the dielectric grain. For example, Ge and / or Ge oxide may be primarily contained within grain boundaries, but some of the Ge and / or Ge oxide may diffuse and reside in the shell within the dielectric grain.

[0084] The core and shell have different molar ratios of the secondary component to the primary component, and for example, the molar ratio of the secondary component to the primary component can change dramatically at the boundary between the core and the shell. Therefore, the boundary between the core and the shell can be easily distinguished and confirmed by transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDS) analysis.

[0085] For example, the core may not include any secondary components or may include only trace amounts of secondary components. Thus, the core may consist solely of a pure primary component free of impurities, and the pure primary component generally has a higher dielectric constant than a primary component doped with an impurity element. Therefore, the core may function to maintain the dielectric constant.

[0086] The shell contains more accessory components than the core. The accessory components doped into the shell's main component (perovskite ABO3 structure) at the B site increase the band gap energy of other rare earth elements and dopant elements diffusing into the dielectric grains. Therefore, the shell acts as a barrier, inhibiting the diffusion of other rare earth elements and dopant elements into the dielectric grains. The shell inhibits the growth of dielectric grains, thereby contributing to the miniaturization of dielectric grains. Furthermore, the accessory components doped into the shell's main component at the A site improve reliability and dielectric constant.

[0087] For example, the average thickness of dielectric layer 111 may be greater than or equal to about 0.05 μm, greater than or equal to about 0.1 μm, or greater than or equal to about 0.2 μm, and less than or equal to about 10 μm, less than or equal to about 5 μm, less than or equal to about 2.5 μm, or less than or equal to about 2.0 μm.

[0088] The average thickness of the dielectric layer 111 can be measured by the following method.

[0089] First, a scanning electron microscope (SEM) image was obtained by observing the cross-section of the sample using a scanning electron microscope.

[0090] The average thickness of the dielectric layer 111 can be: in the SEM image of the cross-sectional sample, when the center point in the length direction (L-axis direction) or the width direction (W-axis direction) of the dielectric layer 111 is used as a reference point, the arithmetic average of the thicknesses of the dielectric layer 111 at 10 points separated from the reference point at predetermined intervals in the length direction (L-axis direction) or the width direction (W-axis direction).

[0091] The intervals between the 10 points may be adjusted according to the size of the SEM image, and may be, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, or about 1 μm to about 10 μm.

[0092] In this case, all 10 points should be located within the dielectric layer 111, and when all 10 points are not located within the dielectric layer 111, the position of the reference point may be changed or the intervals between the 10 points may be adjusted. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used to measure the average thickness of the dielectric layer 111.

[0093] Inner electrode The internal electrodes may include a first internal electrode 121 and a second internal electrode 122. The first internal electrodes 121 and the second internal electrodes 122 are electrodes having different polarities and are alternately arranged to face each other along the T-axis direction with the dielectric layer 111 interposed therebetween. One end of the first internal electrode 121 and one end of the second internal electrode 122 may be exposed through the third surface and the fourth surface of the capacitor body 110, respectively.

[0094] The first and second internal electrodes 121 and 122 may be electrically insulated from each other by the dielectric layer 111 disposed therebetween.

[0095] One ends of the first and second internal electrodes 121 and 122 alternately exposed from the third and fourth surfaces of the capacitor body 110 may be electrically coupled to the first and second external electrodes 131 and 132 , respectively.

[0096] In an embodiment, the first and second internal electrodes 121 and 122 may include a conductive metal and Ge, and as a specific example, may include an alloy of the conductive metal and Ge.

[0097] For example, the conductive metal may further include a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy thereof, for example, an Ag-Pd alloy. For example, when the conductive metal is Ni, the first and second internal electrodes 121 and 122 may include Ni and Ge, and may include, for example, a Ni-Ge alloy.

[0098] In addition, the first and second internal electrodes 121 and 122 may include dielectric particles of the same composition system as that of the ceramic material included in the dielectric layer 111 .

[0099] The first and second internal electrodes 121 and 122 may be formed using a conductive paste including a conductive metal and Ge. A printing method of the conductive paste may use a screen printing method, a gravure printing method, or the like.

[0100] In an embodiment, the dielectric layer 111 may include Ti and Ge, and the internal electrodes 121 and 122 may include Ni and Ge, and when the average content (mol) of Ge relative to 100 mol of Ni in the internal electrodes 121 and 122 is X and the average content (mol) of Ge relative to 100 mol of Ti in the dielectric layer 111 is Y, the relationship between X and Y may satisfy Equation 1.

[0101] [Formula 1] X / Y≥1 For example, in Formula 1, X / Y may be greater than about 1, eg, greater than or equal to about 1.4, or greater than or equal to about 1.6.

[0102] In Formula 1, when the X / Y value is less than about 1, a larger amount of Ge exists in the dielectric layer compared to the internal electrode, which may cause problems such as a decrease in dielectric constant.

[0103] For example, X may be about 0.1 mol to about 15 mol. As a specific example, X may be about 0.25 mol or about 0.5 mol or more, and about 10 mol or less, about 5 mol or less, or about 3 mol or less.

[0104] For example, Y may be from about 0.05 mol to about 10 mol. As specific examples, Y may be greater than or equal to about 0.1 mol, greater than or equal to about 0.2 mol, or greater than or equal to about 0.3 mol, and may be less than or equal to about 5 mol, less than or equal to about 2.5 mol, less than or equal to about 2 mol, or less than or equal to about 1.4 mol.

[0105] When the above numerical range is satisfied, a multilayer ceramic capacitor having improved capacitance, reliability, and temperature characteristics may be realized.

[0106] The method for obtaining the above X value and Y value is as follows.

[0107] First, the multilayer ceramic capacitor 100 is placed in an epoxy mixture and cured, and the L-axis and T-axis sides of the capacitor body 110 are polished to the 1 / 2 point in the W-axis direction, and then placed in a vacuum atmosphere chamber to prepare cross-sectional samples cut from the center of the W-axis direction of the capacitor body 110 along the L-axis and T-axis directions.

[0108] Then, after obtaining a TEM image of the cross-sectional sample, five or more random dielectric layers 111 and five or more random internal electrodes 121 and 122 are selected from the image.

[0109] Then, five points equally spaced in the T-axis direction corresponding to the center of the selected dielectric layer 111 are selected. The Ti content (in moles) and the Ge content (in moles) are measured at the selected points by TEM (transmission electron microscopy)-EDS (energy dispersive X-ray spectroscopy). The arithmetic mean of the Ge content relative to 100 moles of Ti is calculated to obtain the Y value. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used to measure the Y value.

[0110] In addition, five points equally spaced in the T-axis direction corresponding to the centers of the selected inner electrodes 121 and 122 are selected, and the Ni content (mol) and the Ge content (mol) are measured at the selected points by TEM-EDS analysis. The arithmetic mean of the Ge content relative to 100 mol of Ni is calculated to obtain the value X. Even if not described in the present disclosure, other methods and / or tools understood by those skilled in the art may be used to measure the value X.

[0111] For example, the center of dielectric layer 111 may refer to the midpoint between a point on one surface of dielectric layer 111 in the T-axis direction and another point on the other surface of dielectric layer 111 (opposite to the one surface of dielectric layer 111 in the T-axis direction) at the shortest distance from the point, in a cross-section in the L-axis and T-axis directions taken from the center of capacitor body 110 in the W-axis direction. The center of dielectric layer 111 may refer not only to the midpoint but also to an area within ±30% of the average thickness of dielectric layer 111 in the T-axis direction relative to the midpoint.

[0112] For example, the center of the internal electrodes 121 and 122 may refer to the midpoint between a point on one surface of the internal electrodes 121 and 122 in the T-axis direction and another point on the other surface of the internal electrodes 121 and 122 (opposite to the one surface of the internal electrodes 121 and 122 in the T-axis direction) at the shortest distance from the point, in a cross-section in the L-axis and T-axis directions cut from the center of the capacitor body 110 in the W-axis direction. The center of the internal electrodes 121 and 122 may refer not only to the midpoint but also to an area within ±30% of the average thickness of the internal electrodes 121 and 122 in the T-axis direction relative to the midpoint.

[0113] For example, the average thickness of the first and second internal electrodes 121 and 122 may be greater than or equal to about 0.05 μm, greater than or equal to about 0.1 μm, greater than or equal to about 0.2 μm, or greater than or equal to about 0.25 μm, and may be less than or equal to about 2 μm, less than or equal to about 1 μm, less than or equal to about 0.5 μm, less than or equal to about 0.4 μm, or less than or equal to about 0.3 μm.

[0114] The average thickness of the first internal electrode 121 or the second internal electrode 122 may be measured by the following method.

[0115] The average thickness of the first internal electrode 121 or the second internal electrode 122 may be: in an SEM image of a cross-sectional sample, when a center point in the length direction (L-axis direction) or the width direction (W-axis direction) of the first internal electrode 121 or the second internal electrode 122 is used as a reference point, an arithmetic average of the thicknesses of the first internal electrode 121 or the second internal electrode 122 at 10 points spaced apart from the reference point at predetermined intervals in the length direction (L-axis direction) or the width direction (W-axis direction).

[0116] The intervals between the 10 points may be adjusted according to the size of the SEM image, and may be, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, or about 1 μm to about 10 μm.

[0117] In this case, all 10 points should be located within the first inner electrode 121 or the second inner electrode 122. When not all 10 points are located within the first inner electrode 121 or the second inner electrode 122, the position of the reference point may be changed or the intervals between the 10 points may be adjusted. Even if not described in the present disclosure, other methods and / or tools understood by those of ordinary skill in the art may be used to measure the average thickness of the first inner electrode 121 or the second inner electrode 122.

[0118] External electrode The first and second external electrodes 131 and 132 may receive voltages of different polarities and may be electrically connected to the exposed portions of the first and second internal electrodes 121 and 122 , respectively.

[0119] According to the above configuration, when a predetermined voltage is applied between the first external electrode 131 and the second external electrode 132, charges are accumulated between the first internal electrode 121 and the second internal electrode 122 facing each other. At this time, the capacitance of the multilayer ceramic capacitor 100 is proportional to the overlapping area of the first internal electrode 121 and the second internal electrode 122 that overlap each other in the T-axis direction in the active region.

[0120] The first outer electrode 131 may be disposed on the third surface of the capacitor body 110 and may include a first connection portion coupled to the first inner electrode 121 and may include a first band portion disposed at an edge where the third surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces, and the second outer electrode 132 may be disposed on the fourth surface of the capacitor body 110 and may include a second connection portion coupled to the second inner electrode 122 and may include a second band portion disposed at an edge where the fourth surface of the capacitor body 110 intersects with the first and second surfaces and / or the fifth and sixth surfaces.

[0121] The first tape portion may extend from the first connection portion to a portion of the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the second tape portion may extend from the second connection portion to a portion of the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. The first tape portion and the second tape portion may respectively serve to improve the adhesive strength of the first and second external electrodes 131 and 132.

[0122] As an example, each of the first and second external electrodes 131 and 132 may include a sintered metal layer contacting the capacitor body 110 , a conductive resin layer disposed to cover the sintered metal layer, and a plating layer disposed to cover the conductive resin layer.

[0123] The sintered metal layer may include a conductive metal and Ge, and as an example, the sintered metal layer may include an alloy of the conductive metal and Ge.

[0124] The sintered metal layer may include a conductive metal, such as copper (Cu), nickel (Ni), silver (Ag), palladium (Pd), gold (Au), platinum (Pt), tin (Sn), tungsten (W), titanium (Ti), lead (Pb), alloys thereof, or combinations thereof. "The conductive metal includes copper (Cu)" may mean that the conductive metal includes copper (Cu) alone and / or a copper (Cu) alloy. For example, when the conductive metal is Cu, the sintered metal layer may include Cu and Ge, and may include, for example, a Cu-Ge alloy. Furthermore, when the conductive metal includes copper, a metal other than copper may be included in an amount of approximately 5 mol or less based on 100 mol of copper.

[0125] For example, the sintered metal layer may further include glass. As an example, the sintered metal layer may include an oxide-containing composition as the glass, and may include, for example, one or more selected from silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, and alkaline earth metal oxides. The transition metal may be one or more selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), and nickel (Ni). The alkali metal may be one or more selected from lithium (Li), sodium (Na), and potassium (K). The alkaline earth metal may be one or more selected from magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0126] Alternatively, the conductive resin layer is formed on the sintered metal layer and, for example, may be formed to completely cover the sintered metal layer. In addition, the first and second external electrodes 131 and 132 may not include the sintered metal layer, and in this case, the conductive resin layer may be in direct contact with the capacitor body 110.

[0127] The conductive resin layer may extend to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110, and the length of the region (i.e., the stripe portion) where the conductive resin layer extends to the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110 may be longer than the length of the region (i.e., the stripe portion) where the sintered metal layer extends on the first and second surfaces and / or the fifth and sixth surfaces of the capacitor body 110. In other words, the conductive resin layer may be formed on the sintered metal layer and may be formed to completely cover the sintered metal layer.

[0128] The conductive resin layer includes resin and conductive metal.

[0129] The resin included in the conductive resin layer is not particularly limited as long as it has adhesive properties and impact absorption properties and can be mixed with the conductive metal powder to form a paste, and may include, for example, phenolic resin, acrylic resin, silicone resin, epoxy resin, or polyimide resin.

[0130] The conductive metal included in the conductive resin layer serves to electrically connect the conductive resin layer to the first and second internal electrodes 121 and 122 or the sintered metal layer.

[0131] The conductive metal included in the conductive resin layer may have a spherical shape, a flake shape, or a combination thereof. In other words, the conductive metal may be in the form of only a flake shape, or may be in the form of only a spherical shape, or may be in the form of a mixture of a flake shape and a spherical shape.

[0132] Here, the spherical shape may include a shape that is not completely spherical, and may include, for example, a shape in which the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) may be less than or equal to about 1.45. Flake-type powder refers to powder having a flat and elongated shape, and is not particularly limited, but, for example, the ratio of the length of the major axis to the length of the minor axis (major axis / minor axis) may be greater than or equal to about 1.95.

[0133] The first and second external electrodes 131 and 132 may further include a plating layer disposed on an outer side of the conductive resin layer.

[0134] The plating layer may include nickel (Ni), copper (Cu), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), or lead (Pb), or alloys thereof. As an example, each plating layer may be a nickel (Ni) plating layer or a tin (Sn) plating layer, or may be a form in which a nickel (Ni) plating layer and a tin (Sn) plating layer are stacked in sequence, or may be a form in which a tin (Sn) plating layer, a nickel (Ni) plating layer, and a tin (Sn) plating layer are stacked in sequence. Alternatively, each plating layer may include multiple nickel (Ni) plating layers and / or multiple tin (Sn) plating layers.

[0135] The plating layer may improve the mountability to a substrate, structural reliability, durability to the outside, heat resistance, and equivalent series resistance (ESR) of the multilayer ceramic capacitor 100 .

[0136] Method for manufacturing multilayer ceramic capacitor A method of manufacturing a multilayer ceramic capacitor according to another embodiment includes manufacturing a capacitor body including a dielectric layer and an inner electrode, and then forming an outer electrode on an outer side of the capacitor body.

[0137] First, the production of the capacitor body will be described.

[0138] During the manufacturing process of the capacitor body, a dielectric paste and a conductive paste are prepared. The dielectric paste will be formed into a dielectric layer after sintering, and the conductive paste will be formed into an internal electrode after sintering.

[0139] The dielectric paste is prepared, for example, by the following method. Dielectric powder is uniformly mixed by wet mixing, dried, and heat-treated under predetermined conditions to obtain a plasticized powder. Subsequently, an organic vehicle or an aqueous vehicle is added to the plasticized powder and kneaded to prepare a dielectric paste.

[0140] The obtained dielectric paste is formed into a dielectric green sheet by using a technique such as a doctor blade method. In addition, if necessary, the dielectric paste may include an additive selected from various dispersants, plasticizers, dielectrics, subcomponent compounds or glass.

[0141] The conductive paste for the internal electrode may be prepared by kneading a conductive powder made of a conductive metal or alloy with a binder or a solvent.

[0142] As an example, the conductive paste for the internal electrodes may be manufactured to include Ge. For example, the conductive paste for the internal electrodes may be manufactured to include an alloy containing Ge (eg, Ni-Ge alloy) and / or may be manufactured to include Ge oxide (eg, GeO2 powder).

[0143] If necessary, the conductive paste for the inner electrode may include ceramic powder (eg, barium titanate powder) as a co-material. The co-material may function to suppress sintering of the conductive powder during the sintering process.

[0144] A conductive paste for the internal electrodes is applied to the surface of a dielectric green sheet in a predetermined pattern using various printing methods such as screen printing or a transfer method. A dielectric green sheet stack is then obtained by stacking multiple layers of dielectric green sheets having internal electrode patterns formed thereon and then pressing in the stacking direction. At this point, the dielectric green sheets and internal electrode patterns can be stacked so that the dielectric green sheets are positioned in the upper and lower portions of the dielectric green sheet stack in the stacking direction to form a covered area.

[0145] Alternatively, the obtained dielectric green sheet stack may be cut into a predetermined size by dicing or the like.

[0146] Furthermore, if necessary, the dielectric green sheet stack may be cured and dried to remove plasticizers and the like, and then subjected to barrel polishing using a horizontal centrifugal barrel machine or the like. During barrel polishing, unnecessary portions such as burrs generated during cutting can be polished by adding the dielectric green sheet stack, a medium, and a polishing solution to a barrel container and then applying rotational motion, vibration, or the like to the barrel container. Furthermore, after barrel polishing, the dielectric green sheet stack may be washed with a cleaning solution such as water and dried.

[0147] The dielectric green sheet stack is subjected to a binder removal process and a sintering process to obtain a capacitor body.

[0148] The binder removal process is performed under conditions appropriately adjusted according to the main component composition of the dielectric layer and the main component composition of the internal electrode. For example, the binder removal process is performed by increasing the temperature at a temperature increase rate of about 5°C / hour to about 300°C / hour and maintaining the temperature at a holding temperature of about 180°C to about 400°C for about 0.5 hour to about 24 hours. The binder removal process is performed in an air atmosphere or a reducing atmosphere.

[0149] The sintering process may be performed under conditions appropriately adjusted according to the main component composition of the dielectric layer or the main component composition of the inner electrode. For example, the sintering process may be performed at about 1200° C. to about 1350° C. or about 1220° C. to about 1300° C. for about 0.5 hours to about 8 hours or about 1 hour to about 3 hours. The sintering process may be performed under a reducing atmosphere (for example, under a humidified atmosphere of a mixed gas of nitrogen (N2) and hydrogen (H2)). When the inner electrode includes nickel (Ni) or a nickel (Ni) alloy, the oxygen partial pressure in the sintering atmosphere may be about 1.0×10 -14 MPa to about 1.0×10 -10 MPa.

[0150] After the sintering process, an annealing process may be performed. Since the annealing process is a process for reoxidizing the dielectric layer, the annealing process may be performed if the sintering is performed in a reducing atmosphere. The annealing process is performed under conditions appropriately adjusted according to the main component composition of the dielectric layer, etc. For example, the annealing process may be performed at about 950°C to about 1150°C for about 0 hours to about 20 hours by increasing the temperature at a heating rate of about 50°C / hour to about 500°C / hour. The annealing process may be performed at about 1.0×10 -9 MPa to about 1.0×10 -5 The annealing process was performed at an oxygen partial pressure of MPa.

[0151] For example, wetting of nitrogen, mixed gas, or the like can be performed by using a wetting agent (e.g., water) during the binder removal process, the sintering process, or the annealing process. The temperature of the wetting agent (e.g., water) used here can be about 5° C. to about 75° C. The binder removal process, the sintering process, and the annealing process can be performed sequentially or independently.

[0152] Alternatively, the third and fourth surfaces of the capacitor body may be subjected to surface treatment such as sandblasting, laser irradiation, or barrel polishing. This surface treatment may expose the ends of the first and second inner electrodes to the third and fourth surfaces, which may enhance electrical bonding between the first and second outer electrodes and the first and second inner electrodes and facilitate formation of an alloy portion.

[0153] Subsequently, a paste for forming a sintered metal layer is applied on the outer side of the obtained capacitor body and sintered to form a sintered metal layer of the external electrode.

[0154] The paste for forming the sintered metal layer can include conductive metal and glass. Conductive metal and glass are the same as above and are therefore not repeated. In addition, optionally, the paste for forming the sintered metal layer can include the secondary component such as adhesive, solvent, dispersant, plasticizer or oxide powder. For example, the adhesive can be ethyl cellulose, acrylic acid or butyral, and the solvent can be an organic solvent or an aqueous solvent such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene.

[0155] Methods for applying the paste for forming the sintered metal layer on the outer side of the capacitor body may include various printing methods (such as screen printing), dipping, coating using a dispenser, or spraying using a sprayer. The paste for forming the sintered metal layer is applied to at least the third and fourth surfaces of the capacitor body, and optionally, to portions of the first, second, fifth, and / or sixth surfaces of the strip portions of the first and second external electrodes.

[0156] Subsequently, the capacitor body coated with the paste for forming a sintered metal layer is dried at about 700° C. to about 1000° C. and sintered for about 0.1 hour to about 3 hours to form a sintered metal layer.

[0157] Alternatively, a paste for forming a conductive resin layer is applied and cured on the outer side of the sintered metal layer to form the conductive resin layer.

[0158] The paste for forming the conductive resin layer may include resin and conductive metal, and optionally, may include non-conductive filler. Because the description of conductive metal and resin is the same as above, repeated description will be omitted. In addition, optionally, the paste for forming the conductive resin layer may include secondary components such as adhesive, solvent, dispersant, plasticizer or oxide powder. For example, the adhesive may be ethyl cellulose, acrylic acid or butyral, and the solvent may be an organic solvent or an aqueous solvent such as terpineol, butyl carbitol, ethanol, methyl ethyl ketone, acetone or toluene.

[0159] For example, the method of forming the conductive resin layer may include: immersing the capacitor body 110 in a paste for forming the conductive resin layer and curing the paste, or printing the paste for forming the conductive resin layer on the outside of the sintered metal layer using screen printing, gravure printing, etc., or coating the paste for forming the conductive resin layer on the outside of the sintered metal layer, and then curing the paste.

[0160] Subsequently, a plating layer is formed on the outer side of the conductive resin layer.

[0161] For example, the plated layer may be formed by a plating method, or may be formed by a sputtering method or an electrodeposition method.

[0162] Hereinafter, specific examples of the present disclosure will be presented. However, the following examples are only intended to specifically illustrate or describe the present disclosure and should not be construed as limiting the scope of the present disclosure.

[0163] (Example) Example 1 The multilayer ceramic capacitor of Example 1 was manufactured by weighing Ge and adjusting the oxygen partial pressure conditions so that the content of Ge per 100 mol of Ti in the finally formed multilayer ceramic capacitor was 0.05 mol.

[0164] The Ge content in the multilayer ceramic capacitor was measured according to the following method.

[0165] First, a multilayer ceramic capacitor according to Example 1 was prepared as a sample. Then, 0.1 g of the sample was weighed and placed in a pressure bottle, and 6 mL of hydrochloric acid and 2 mL of nitric acid were added to the pressure bottle to prepare a mixture. The mixture was heat-treated at about 180 ° C for about 1 hour and further ultrasonicated to prepare a dissolved sample. The dissolved sample was filtered with a 0.45 μm filter and analyzed for Ti content (wt%) and Ge content (wt%) by using an inductively coupled plasma-optical emission spectrometer (ICP-OES). After converting the wt% of each element to mol%, the mol% of Ge was converted based on 100 mol of Ti to obtain the Ge content in the multilayer ceramic capacitor.

[0166] For reference, the wt % of each of the Ni element, Ba element, Ti element, and Ge element of the multilayer ceramic capacitors according to Examples 2 to 4 was respectively measured by the ICP-OES analysis method, and the results are shown in Table 2. After the wt % of each element was converted into mol %, the mol % of Ge was converted based on 100 mol of Ti and then provided as “Ge content in multilayer ceramic capacitor (mol / 100 mol of Ti)” in Table 1.

[0167] In addition, the average content (mol) of Ge based on 100 mol of Ni in the inner electrodes and the average content (mol) of Ge based on 100 mol of Ti in the dielectric layers of the multilayer ceramic capacitors according to Examples 1 and 2 were measured and the results are shown in Table 3.

[0168] The average content of Ge in the internal electrodes and the dielectric layer can be obtained by the following method.

[0169] First, after curing the multilayer ceramic capacitor according to Example 1 by placing it in an epoxy mixture, the L-axis direction and T-axis direction sides of the capacitor body are polished to the 1 / 2 point in the W-axis direction, and then placed in a vacuum atmosphere chamber to prepare cross-sectional samples cut along the L-axis direction and the T-axis direction from the center of the W-axis direction of the capacitor body.

[0170] Then, after obtaining a TEM image of the cross-sectional sample, any five or more dielectric layers and internal electrodes are respectively selected from the image.

[0171] Subsequently, five equally spaced points corresponding to the centers of the selected dielectric layers were selected, and the Ti content (mol) and the Ge content (mol) were measured by TEM (transmission electron microscopy)-EDS (energy dispersive X-ray spectrometry) analysis, and then the arithmetic mean of the Ge content relative to 100 mol of Ti was calculated to obtain the Y value.

[0172] In addition, 5 points at equal intervals respectively corresponding to the centers of the selected inner electrodes were selected to measure the Ni content (mol) and the Ge content (mol) by TEM-EDS analysis, and then the arithmetic mean of the Ge content relative to 100 mol of Ni was calculated to obtain the X value.

[0173] Examples 2 to 9 and Comparative Examples 1 to 3 Each of the multilayer ceramic capacitors according to Examples 2 to 9 and Comparative Examples 1 to 3 was manufactured by weighing Ge and adjusting the oxygen partial pressure conditions so that the Ge content in the finally formed multilayer ceramic capacitor was as shown in Table 1.

[0174] (Evaluation example) Evaluation Example 1: Capacitance Measurement The capacitance of the multilayer ceramic capacitors according to Examples 1 to 9 and Comparative Examples 1 to 3 was measured by using an LCR meter under the conditions of 1 kHz and AC 0.5 V.

[0175] The relative values of the other examples and the comparative example were calculated using the capacitance of the comparative example 1 as the reference value 1, and the results are shown in Table 1.

[0176] Evaluation Example 2: MTTF (Mean Time to Failure) Measurement The MTTF (Mean Time to Failure) of the multilayer ceramic capacitors according to Examples 1 to 9 and Comparative Examples 1 to 3 were measured by performing a high temperature load test under the conditions of 125° C. and 8V.

[0177] Here, the mean time to failure is the time when the insulation resistance becomes 10 kΩ or less, and relative values of other examples and comparative examples are calculated using the MTTF of Comparative Example 1 as Reference Value 1, and the results are shown in Table 1.

[0178] Evaluation Example 3: Evaluation of Satisfaction with Temperature Characteristics The capacitance change rates of the multilayer ceramic capacitors according to Examples 1 to 9 and Comparative Examples 1 to 3 were measured by increasing the temperature by 1°C from -55°C to 85°C. Specifically, after the multilayer ceramic capacitors were held for 1 minute under the conditions of 1 kHz, 0.1 Vrms, and AC to measure capacitance, the capacitance change rate at each temperature was calculated according to Formula 2 based on 25°C.

[0179] [Formula 2] Capacitance change rate at T℃ (%) = {(C[T℃]-C[25℃]) / C[25℃]}×100 *C[T℃]=Capacitance measured at T℃ If the capacitance change rate at each temperature calculated according to Formula 2 is within ±15%, O (pass) is given, but if any one of the capacitance change rates at each temperature calculated according to Formula 2 is not within ±15%, X (fail) is given, and the results are shown in Table 1.

[0180] (Table 1)

[0181] Referring to Table 1, the multilayer ceramic capacitors of Examples 1 to 9 have a Ge content of about 0.01 mol to about 20 mol based on 100 mol of Ti, exhibiting higher capacitance than that of Comparative Example 1 and greater MTTF than that of Comparative Example 1, thereby exhibiting high reliability and overall excellent temperature characteristics.

[0182] On the other hand, the Ge content in the multilayer ceramic capacitor of Comparative Example 1 was less than 0.01 mol based on 100 mol of Ti, and it was confirmed that Comparative Example 1 exhibited deterioration in capacitance characteristics, reliability, and temperature characteristics compared with the examples.

[0183] Furthermore, the multilayer ceramic capacitors of Comparative Examples 2 and 3, in which the Ge content based on 100 mol of Ti was greater than 20 mol, exhibited low MTTF and degraded reliability compared to the examples.

[0184] (Table 2)

[0185] (Table 3)

[0186] Referring to Table 1 and Table 3, the multilayer ceramic capacitors of Examples 1 and 2 were both confirmed to exhibit X / Y greater than or equal to 1, thereby achieving excellent capacitance characteristics, reliability, and temperature characteristics.

[0187] While the present disclosure has been described in conjunction with what are presently considered to be practical example embodiments, it should be understood that the present disclosure is not limited to the disclosed example embodiments, but rather is intended to cover various modifications and equivalents included within the spirit and scope of the appended claims.

Claims

1. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode disposed on an outer surface of the capacitor body, wherein the multilayer ceramic capacitor comprises Ti and Ge, and In the multilayer ceramic capacitor, a content of Ge is 0.01 mol to 20 mol based on 100 mol of Ti.

2. The multilayer ceramic capacitor according to claim 1, wherein The dielectric layer includes Ti and Ge, and the inner electrode includes Ni and Ge, and When the average molar content of Ge in the inner electrode relative to 100 moles of Ni in the inner electrode is X, and When the average molar content of Ge in the dielectric layer relative to 100 moles of Ti in the dielectric layer is Y, The relationship between X and Y satisfies Equation 1: [Formula 1] X / Y≥1.

3. The multilayer ceramic capacitor according to claim 2, wherein X is 0.1 mol to 15 mol.

4. The multilayer ceramic capacitor according to claim 2, wherein Y is 0.05 mol to 10 mol.

5. The multilayer ceramic capacitor according to claim 1, wherein The dielectric layer includes a plurality of dielectric grains and a grain boundary between at least two dielectric grains among the plurality of dielectric grains. The plurality of dielectric grains include a main component and a subcomponent, and The main components include: Ba m TiO3, where 0.995≤m≤1.010, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.010, 0≤x≤0.10, 0 <y≤0.20, Ba m (Ti 1-x Zr x )O3, where 0.995≤m≤1.010, 0 <x≤0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20, or A combination of them.

6. The multilayer ceramic capacitor according to claim 5, wherein The secondary components include Ge, Zr, Dy, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ga, In, Ba, La, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Ho, Er, Tm, Yb, Lu, Hf or a combination thereof.

7. The multilayer ceramic capacitor according to claim 1, wherein The inner electrode has an average thickness of 0.05 μm to 2 μm.

8. The multilayer ceramic capacitor according to claim 1, wherein The average thickness of the dielectric layer is 0.05 μm to 10 μm.

9. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode disposed on an outer surface of the capacitor body, Wherein, the multilayer ceramic capacitor comprises Ti and Ge, In the multilayer ceramic capacitor, the content of Ge is 0.01 mol to 20 mol based on 100 mol of Ti, The dielectric layer includes a plurality of dielectric grains and grain boundaries between at least two of the plurality of dielectric grains, and The grain boundaries include Ge, Ge oxide, or a combination thereof.

10. The multilayer ceramic capacitor according to claim 9, wherein The plurality of dielectric grains include a main component and a subcomponent, and The main components include: Ba m TiO3, where 0.995≤m≤1.010, (Ba 1-x Ca x ) m (Ti 1-y Zr y )O3, where 0.995≤m≤1.010, 0≤x≤0.10, 0 <y≤0.20, Ba m (Ti 1-x Zr x )O3, where 0.995≤m≤1.010, 0 <x≤0.10, (Ba 1-x Ca x ) m (Ti 1-y Sn y )O3, where 0.995 ≤ m ≤ 1.010, 0 ≤ x ≤ 0.10, 0 < y ≤ 0.20, or A combination of them.

11. The multilayer ceramic capacitor according to claim 10, wherein The secondary components include Ge, Zr, V, Mn, Cr, Si, Al, Mg, Sn, Sb, Ba, Hf, Ga, In, La, Y, Ac, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or a combination thereof.

12. The multilayer ceramic capacitor according to claim 10, wherein The plurality of dielectric grains further include Ge, Ge oxide, or a combination thereof.

13. The multilayer ceramic capacitor according to claim 9, wherein The inner electrode includes a conductive metal and Ge.

14. The multilayer ceramic capacitor according to claim 13, wherein The inner electrode includes an alloy containing a conductive metal and Ge.

15. The multilayer ceramic capacitor according to claim 9, wherein The external electrode includes a sintered metal layer in contact with the capacitor body, and The sintered metal layer includes a conductive metal and Ge.

16. The multilayer ceramic capacitor according to claim 9, wherein The inner electrode has an average thickness of 0.05 μm to 2 μm.

17. The multilayer ceramic capacitor according to claim 9, wherein The average thickness of the dielectric layer is 0.05 μm to 10 μm.

18. A multilayer ceramic capacitor comprising: a capacitor body including a dielectric layer and inner electrodes; as well as an outer electrode disposed on an outer surface of the capacitor body, wherein the dielectric layer comprises Ti and Ge, and the inner electrode comprises Ni and Ge, and When the average molar content of Ge in the inner electrode relative to 100 moles of Ni in the inner electrode is X, and When the average molar content of Ge in the dielectric layer relative to 100 moles of Ti in the dielectric layer is Y, The relationship between X and Y satisfies Equation 1: [Formula 1] X / Y≥1.

19. The multilayer ceramic capacitor according to claim 18, wherein The dielectric layer includes Ge in the form of Ge oxide, and the internal electrode includes Ge in the form of an alloy.

20. The multilayer ceramic capacitor of claim 19, wherein In the multilayer ceramic capacitor, a content of Ge is 0.01 mol to 20 mol based on 100 mol of Ti.

21. The multilayer ceramic capacitor of claim 20, wherein The external electrode includes Ge.

22. A method of manufacturing a multilayer ceramic capacitor, comprising: coating a conductive paste on a dielectric green sheet to form an internal electrode pattern on the dielectric green sheet, stacking a plurality of the dielectric green sheets having the inner electrode patterns formed thereon to form a dielectric green sheet stack, and In 1.0×10 -14 MPa to 1.0×10 -10 The dielectric green sheet stack is sintered at an oxygen partial pressure of 100 MPa to form a capacitor body.

23. The method for manufacturing a multilayer ceramic capacitor according to claim 22, further comprising: -9 MPa to 1.0×10 -5 The capacitor body is annealed at an oxygen partial pressure of 100 MPa.

24. The method for manufacturing a multilayer ceramic capacitor according to claim 22, wherein: The conductive paste includes Ge oxide and / or an alloy containing Ge.

25. The method for manufacturing a multilayer ceramic capacitor according to claim 24, wherein The multilayer ceramic capacitor includes Ti, and in the multilayer ceramic capacitor, a content of Ge is 0.01 mol to 20 mol based on 100 mol of Ti.

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